here i went to this site: https://www.zameen.com/blog/mohenjodaro-harappa-history-facts-tourism.html and found some information on Harappa and Mohenjo-Daro, and i (in my own words) put together this:
Explanation:
The significance of Harappa and Mohenjo_Daro's contributions to ancient Indian history was that some of the most incredible secrets of the Indus Valley Civilization were discovered. The ruins were also the very first evidence of Harappan civilization from thousands of years ago. Both sites prove that the northwestern region of South Asia was home to the Indus Valley Civilization from 3,300 BC to 1,900 BC. Remains of the Bronze Age fortified city were found at Harappa. Harappa is also the oldest known civilization.